A wide range of well-directed and motivated species-typical behaviors can be elicited by stimulation of the hypothalamus in a number of species. A great deal of evidence indicates that the hypothalamus produces complex behaviors by acting through divergent descending connections to separate response mechanisms in the lower brainstem. The author has recently shown that complex behaviors, such as predatory-like attack, threat, eating, and grooming, can be elicited by stimulation of localized zones in the pons and cerebellum of cats. The proposed research is intended to further extend the localization of central behavioral systems into lower brainstem areas through electrical brain stimulation mapping of the medulla and caudal pons in free-moving cats. It seems likely that neurobehavioral systems may perform different integrating functions at different levels of the brainstem, rather than lower areas serving merely as passive discharge paths from more rostral regions such as the hypothalamus. The behaviors induced by lower brainstem stimulation will, therefore, be further tested to determine their behavioral and motivational characteristics. These texts will include a determination of the specificity of the elicited behaviors for appropriate goal objects, an assessment of whether the behaviors are motivated, and an analysis of the individual elements of the elicited behaviors. These studies should give some indication of the functional organization within brainstem behavioral systems.